报告题目：Ab initio calculation of deformed nuclei and the nuclear matrix elements of neutrinoless double beta decay with multi-reference in-medium similarity renormalization group
报告人：Dr. Jiangming Yao
（Facility for Rare Isotope Beams, Michigan State University）
报告时间：2019年8月15日（周四）下午3:30
报告地点：北京大学物理学院西楼113室
联系人：孟杰（mengj@pku.edu.cn）
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Abstract:
The discovery that neutrinos oscillate has increased the significance of neutrinoless double beta decay (NLDBD). The search for this lepton-number-violating process has become a priority in nuclear and particle physics. It provides a way to determine neutrino mass from a measured half life if the nuclear matrix element (NME) is known. Since the NME cannot be measured, a first-principles calculation is crucial. Recently, several groups have begun programs to calculate the NMEs from first principles. Applying ab initio methods to the NLDBD decay, however poses a major challenge. The nuclei that are used in experiment are generally heavier and more structurally complicated than those examined so far. Among the ab initio methods that can be applied to heavier and defomed nuclei, the in-medium similarity renormalization group (IM-SRG) which is related to the coupled-cluster method seems particularly promising because the time and memory required to complete a calculation depend as a polynomial on the nuclear mass.
In this talk, I will introduce a novel multi-reference framework for generally deformed nuclei by combining the IM-SRG with the generator coordinate method, which we use to build collective correlations into reference states that are the basis for subsequent renormalization-group evolution. In particular, I will show the first application of this framework for the NME of NLDBD from 48Ca to 48Ti starting from a two plus three-nucleon interaction derived from chiral effective field theory.
